Various sophisticated 1D vdW heterostructures that could be built using more than one TMDC material. (A) Radial junctions where two TMDC nanotubes are at different shells; (B) axial junctions where two TMDCs are at the same shell connecting each other (in this case inner CNT is hidden to reveal the junction interface); (C) alloy nanotubes where different metal atoms and/or different chalcogen atoms are fully mixed; (D) Janus nanotubes where inner and outer surfaces have different chalcogen atoms.